Cyanine dyes containing a cyclopentanone nucleus

ABSTRACT

Novel cyanine dyes containing a cyclopentanone nucleus in the methine chain are prepared by the acid hydrolysis of cyanine enamine derivatives. These cyanine dyes are spectral sensitizers for photographic silver halide emulsions. A number of the new dyes extend the sensitivity of photographic silver halide emulsions into the red and near infra-red regions of the spectrum.

United States Patent [191 Brooker et al.

[ 1 CYANINE DYES CONTAINING A CYCLOPENTANONE NUCLEUS [7 5] Inventors: Leslie G. S. Brooker; Arthur Fumia,

Jr., both of Rochester, N.Y.

[73] Assignee: Eastman Kodak Rochester, NY.

[22] Filed: Feb. 24, 1970 [21] Appl. No.: 17,003

Related 1.1.8. Application Data [62] Division of Ser. No. 656,647, July 28, 1967, abandoned.

Company,

[52] US. Cl ..260/240.4, 96/130, 260/240 R [51] Int. Cl. ..C09b 23/02 [58] Field of Search ..260/240 R, 240.4

[5 6] References Cited FOREIGN PATENTS OR APPLICATIONS 862,444 3/1961 Great Britain ..260/240 [451 Feb. 6, 1973 OTHER PUBLICATIONS Szmuszkovicz, Advances in Organic Chemistry, Methods and Results," Volume 4, Raphael et al. (ed.), lnterscience, New York (1963), pp. 10, 22-25, 38 and 47.

Primary Examiner-*l-lenry R. Jiles Assistant Examiner-G. Thomas Todd Attorney-Robert W. Hampton and Michael R. Chipaloski [57] ABSTRACT 8 Claims, No Drawings CYANINE DYES CONTAINING A CYCLOPENTANONE NUCLEUS This application is a division of our copending application Serial No. 656,647 filed July 28, 1967, now abandoned.

This invention relates to novel photographic materials, and more particularly to a new class of cyanine dyes containing a cyclopentanone nucleus in the methine chain, to novel spectrally sensitized photographic silver halide emulsions and elements prepared therewith, and to the preparation of these dyes and photographic materials.

It is well known that cyanine dyes extend the sensitivity of photographic silver halide emulsions. However, this class includes whole groups of dye compounds which have no sensitizing ability or which even have a desensitizing effect. The number of sensitizers of this class which can be used in practice is further limited by the strict requirements that a really useful sensitizer must meet, when incorporated into silver halide emulsion layers. For example, the clearness of the layers and images produced therein must not be reduced by the presence of the sensitizer, and stability on storage, particularly as regards freedom from fogging and degree of sensitization must be maintained. Furthermore, the gradation in both the fresh and in the aged condition must remain unchanged at the required value. These requirements are especially applicable to sensitizers for color photographic processes, which sensitizers in addition, need to have a particularly high sensitizing action and also a special selectivity.

We have now found that certain cyanine dyes containing a cyclopentanone nucleus in the methine chain are especially well adapted to fill the above-mentioned requirements, and thus provide a new class of excellent spectral sensitizers for both black and white and color photographic materials and processes. A number of these new dyesextend the sensitivity of photographic silver halide emulsions into the red and near infra-red regions of the spectrum.

It is, accordingly, an object of the our invention to provide a new class of cyanine dyes that are useful spectral sensitizers for photographic silver halide emulsions.

Another object is to provide novel photographic silver halide emulsions containing one or more of the new dyes of the invention, and novel photographic elements prepared therewith.

A further object is to provide means for preparing the new dyes and photographic materials of the invention.

Other objects will become apparent from a consideration of the general description and examples, and the appended claims.

The new class of cyanine dyes of the invention are represented by the following general formulas:

and

wherein m and m each represents a positive integer of from 1 to 2, R and R, each represents an alkyl group, preferably a lower alkyl containing from one to four carbon atoms, e.g., methyl, ethyl, propyl, isopropyl, butyl, hexyl, decyl, dodecyl, etc., a substituted alkyl group, preferably a lower group containing one to four carbon atoms, such as a hydroxyalkyl group, e.g., B- hydroxyethyl, y-hydroxypropyl, w-hydroxybutyl, etc., an alkoxyalkyl group, e.g., ,B-methoxyethyl, w-butoxybutyl, etc., a carboxyalkyl group, e.g., B-carboxyethyl, w-carboxybutyl, etc., a sulfoalkyl group, e.g., B-sulfoethyl, m-sulfobutyl, etc., a sulfatoalkyl group, e.g., B- sulfatoethyl, w-sulfatobutyl, etc., an acyloxyalkyl group, e.g., B-acetoxyethyl, w-propionyloxybutyl, etc., an alkoxycarbonylalkyl group, e.g., B-methoxycarbonylethyl, w-ethoxycarbonylbutyl, etc., an ally] group, an aralkyl group, e.g., benzyl, phenethyl, etc., or an aryl group, e.g., phenyl, tolyl, chlorophenyl, sulfophenyl, carboxyphenyl, etc., and and Z and Z each represents the nonmetallic atoms required to complete a 5- to 6 membered heterocyclic nucleus including a thiazole nucleus (e.g., thiazole, methylthiazole, 4-phenylthiazole, S-methylthiazole, S-phenylthiazole, 4,5- dimethylthiazole, 4,5-diphenylthiazole, 4-(2-thienyl)thiazole, etc.), a benzothiazole nucleus (e.g.,

benzothiazole, 4-chlorobenzothiazole, 5- chlorobenzothiazole, 6-chlorobenzothiazole, 7- chlorobenzothiazole, 4-methylbenzothiazole, 4- methylbenzothiazole, 6-methylbenzothiazole, 5-

bromobenzothiazole, 6-bromobenzothiazole, 4-phenylbenzothiazole, S-phenylbenzothiazole, 4-methoxybenzothiazole, S-methoxybenzothiazole, 6-methoxybenzothiazole, 5-iodobenzothiazole, 6- iodobenzothiazole, 4-ethoxybenzothiazole, S-ethoxybenzothiazole, tetrahydrobenzothiazole, 5 ,6- dimethoxybenzothiazole, 5 ,6-dioxymethylenebenzothiazole, S-hydroxybenzothiazole, 6- hydroxybenzothiazole, etc.), a thianaphtheno-7, 6, 4,5-thiazole, etc.), an oxazole nucleus (e.g., 4- methyloxazole, S-methyloxazole, 4-phenyloxazole, diphenyloxazole, 4-ethyloxazole, 4,5-dimethyloxazole, S-phenyloxazole, etc.), a benzoxazole nucleus (e.g., benzoxazole, 5-chlorobenzoxazole, S-methylbenzoxazole, S-phenylbenzoxazole, 6-methylbenzoxazole, 5 ,6-

dimethylbenzoxazole, 4,6-dimethylbenzoxazole, 5- methoxybenzoxazole, S-ethoxybenzoxazole 6chlorobenzoxazole, 6-methoxybenzoxazole, 5

hydroxybenzoxazole, 6-hydroxybenzoxazole, etc.), a naphthoxazole nucleus (e.g., a-naphthoxazole, BB- naphthoxazole, B-naphthoxazole, etc.), those of the selenazole series (e.g., 4-methylselenazole, 4-phenylselenazole, etc.), a benzoselenazole nucleus (e.g.,

benzoselenazole, Schloroselenazole, S-methoxybenzoselenazole, S-hydroxybenzoselenazole, tetrahydrobenzoselenazole, etc.), a naphthoselenazole nucleus (e.g., a-naphthoselenazole, B,,B- naphthoselenazole, B-naphthoselenazole, etc.), a

thiazoline nucleus (e.g., thiazoline, 4-methylthiazoline, etc.), a 2-quinoline nucleus (e.g., quinoline, 3- methylquinoline, S-methylquinoline, 7-methylquinoline, 8-methylquinoline, 6-chloroquinoline, 6-methoxyquinoline, 6-ethoxyquinoline, 6-hydroxyquinoline, 8-

hydroxyquinoline, etc.), a 4-quinoline nucleus (e.g., 6-

alkylbenzimidazole nucleus (e.g., l-methylbenzimidazole, 1-butyl-4-methylbenzimidazole, lethyl-5,6-dichlorobenzimidazole, etc.), a l-alkylnaphthimidazole nucleus (e.g., l-ethyl-anaphthimidazole, l-methyl-B-naphthimidazole, etc.), and the like. The symmetrical dyes of the invention coming under Formula II above which contain benzothiazole nuclei are particularly useful spectral sensitizers for photographic silver halide emulsions and are preferred.

The new cyanine dyes of the invention as defined by Formula I above can be readily prepared by hydrolysis of a compound of the general formula:

HzC-CH2 H CH2 wherein n, R and Z are as previously defined, and X represents an acid anion such as chloride, bromide, iodide, thiocyanate, sulfamate, perchlorate, ptoluenesulfonate, methyl sulfate, ethyl sulfate, etc., in an aqueous solution of a strong mineral acid such as hydrochloric acid, sulfuric acid, etc., at elevated temperatures and preferably at refluxing temperatures of the reaction mixture, until the hydrolysis reaction is completed. The dye products are then separated from the reaction mixtures by chilling and purified by one or more recrystallizations from suitable solvents such as pyridine/methanol, etc.

The new cyanine dyes of the invention as defined by Formula II above are prepared by a similar hydrolysis method as described above, except that here the compound that is hydrolyzed is represented by the following general formula:

wherein m,n, R, R,, X, Z and Z, are as previously defined.

The intermediate dye compounds defined by Form ula Ill above can be conveniently prepared by condensing approximately 1 mole of N-cyclopentenylpyrrolidine with 1 mole of a compound of the general formula:

wherein n, R,X and Z are as previously defined.

The symmetrical intermediate dye compounds defined by Formula IV above can be conveniently prepared for example, by condensing approximately 1 mole N-cyclopentenylpyrrolidine with 2 moles of a compound selected from above Formula V. To prepare the unsymmetrical intermediate dye compounds of Formula IV above, an appropriate compound of Formula III above is condensed with an appropriate compound of Formula V above, in approximately equimolar proportions.

For further details concerning the preparation of cyanine dye intermediates defined by Formulas III and IV above, reference can be had to copending applica- 1966, now U. S. Pat. No. 3,506,655,655 issued April 14, 1970 wherein the preparation of such intermediate dyes are described and claimed.

The following examples further illustrate this invention.

Example 1 2,5-Bis[(3-ethyl-2-benzothiazolinylidene)ethylidene lcyclopentanone JJzHi tion of the starting material had disappeared. Afterchilling, the solid was collected on a funnel, washed with acetone and dried. After two recrystallizations from pyridine/methanol, the yield of purified dye was 2.1 g. (46 percent) m.p. 246-247C. decomposes.

In place of the 3,3"-dieth yl-l0,l2-etliylene-ll-(lpyrrolidinyl) thiacarbocyanine iodide in the above example, there can be substituted an equivalent amount of, for example, 3,3-diethyl-l0,l2-ethylene-l l-( l-pyrrolidinyl)oxatricarbocyanine salt such as the chloride,

tion of R. A. Jeffreys, Ser. No. 518,0l0filed Jan. 3,

l l-( l-pyrrolidinyl)selenotricarbocyanine salt or a 3,3- diethyl- 10,1 2-ethylene-l l-( l-pyrrolidinyl)thiazolotricarbocyanine salt, and the like, to give the corresponding cyanine dyes of the invention having generallg similar spectral sensitizing properties when incorporated in photographic silver halide emulsions.

'Exam 'le 2 2,5-Bis[(l-ethylnaphtho[1,2-d1thiazolin-2- ylidene)ethylidene ]cyclopentanone H-Hs 3,3 '-Diethyl-l0,l2 ethylene-1 l-(1-pyrrolidinyl)- 4,5 ,4 ',5 '-dibenzothiatricarbocyanine p-toluenesulfonate (3.9 g., l mol.),water (75 ml.), ethanol (200 ml.), and 36 percent hydrochloric acid (5 ml.) were heated under reflux with stirring. The mixture was diluted several times with additional acid and water with refluxing continued until the absorption of the starting material had disappeared. After chilling,.the solid was collected on a funnel, washed with methanol and dried. After two recrystallizations from pyridine/methanol, the yield of purified dye was 0.9 g. (32 percent), m.p. 275-276C. dec.

In place of the 3,3'-diethyl-l0,l2-ethylene-(l rolidinyl)-4,5 ,4,5 '-dibenzothiacarbocyanine toluenesulfonate in the above example there can be substituted an equivalent amount of, for example, 3,3- diethyl-10,1 2-ethylene-( 1-pyrrolidinyl)-4,5,4',5 dibenzoxatricarbocyanine salt such as the chloride, bromide, iodide, etc., to give the correspondingcyanine dye of the invention having generally similar spectral sensitizing properties for photographic silver halide emulsions. 1

EXAMPLE 3 2,5-Bis[1,3,3-trimethyl-2-indolinylidene)ethylidene1- cyclopentanone -pyrl0,12-Ethylene-l,1',3,3,3',3-hexamethyl-ll-(lpyrrolidinyl)indotricarbocyanine iodide (6.3 g., 1 mol.) was treated with water and 36 percent. hydrochloric acid in the same manner as example 2. After two recrystallizations from pyridine/methanol, the yield of purified dye was 1.1 g. (25 percent), m.p. 265-266C. dec.

EXAMPLE 4 2[(3-Ethyl-2-benzothiazolinylidene)ethylidenelcyclopentan one C zHi 3-Ethyl-2-{2- [2-( l-pyrrolidinyl)cyelopentenyl]vinyl} benzothiazolium iodide (6.0 g., lmol.) was treated with water and 36 percent hydrochloric acid in the manner as example 2. After two recrystallizations from pyridine/methanol, the yield of purified dye was 1.1 g. (31 percent), m.p. 230-231C. dec.

In place of the 3- ethyl-2-{2-[2-(l-pyrrolidinyl)cyclopentyl] benzothiazolium iodide in the above example, there can be substituted an equivalent amount of, for example, 3-ethyl-2-{2-[2-(l-pyrrolidinyl)cyclopentyl]vinyl}benzoxazolium salt such as the bromide, chloride, iodide, etc., or the corresponding selenazolium salts, or the corresponding thiazolium salts, and the like, to give the corresponding cyanine dyes of the invention that likewise extend the sensitivity of photographic silver halide emulsions.

The above prepared dyes of the invention were then tested in a silver chlorobromide emulsion. The dyes,

'dissolved in suitable solvents, were added to separate portions of the emulsion, at the concentrations indicated in the following Table 1. After digestion at -52C. for about 10 minutes, the emulsions were coated at a coverage of 459 mg. of silver and 1,040 mg. of gelatin per square foot on a cellulose acetate film support. A sample of each coating was exposed on an Eastman 1B sensitometer and to a wedge spectrograph, processed for 5 minutes in Kodak DK-5O developer Handbook of Chemistry and Physics," 30th edition, 1947, Chemical Rubber Publishing Co., Cleveland, Ohio, page 2,558) having the following composition:

N-methyl-p-aminophenol sulfate 2.5 g. Sodium Sulfite (desiccated) 30.0 g. l-lydroquinone 2.5 g. Sodium metaborate 10.0 g. Potassium bromide 0.5 g.

Water to make 1.0 liter and then fixed in a conventional sodium thiosulfate fix- 5 ing bath, washed and dried. The sensitizing values obtained are shown in the following Table 1.

The following examples illustrate the preparation of the intermediate dye compounds employed in the procedures of above examples 1 to 4 to prepare the cyanine dyes of the invention. As indicated previously, additional details for the preparation of these and related dye intermediates can be had by reference to the aforementioned R. A. Jeifreys copending application, Ser. No. 518,010, filed Jan. 3, 1966.

EXAMPLE 3 ,3 -Diethyl-l0, l 2-ethylene-l l-( l-pyrrolidinyl)- thiatricarbocyanine iodide EXAMPLE 6 3,3'-Diethyl-10,12-ethylene-l 1- 1-pyrrolidinyl)- osomm um p-toluenesulfonate (21 g., 2 mols. 5 percent), N-

EXAMPLE 7 10,1 Z-Ethylene-l ,l,3,3,3,3'-hexamethyl-l l-( l-pyrrolidinyl)indotricarbocyanine iodide 2-( 2-Acetanilidovinyl)-l ,3 ,3-trimethylindolium iodide (9.4 g., 2 mols. 5 percent), N-cyclopentenyl-- pyrrolidine (1.4 g., 1 mol.), and triethylenediamine (2.2 g., 1 mo]. percent) were dissolved in N,N- dimethylacetamide'(25 m1.) and heated on a steam bath, with stirring, for 15 minutes. After chilling, the reaction mixture was filtered and the filtrate treated with ether to precipitate the product. The crude product was collected on a filter and after two recrystallizations from methanol, the yield of purified dye was 2.1 g. (33 percent), m.p. 242243C. dec.

EXAMPLE 8 3-Ethyl-2 2-[2-( l-pyrrolidinyl)cyclopentenyl]-vinyl benz oth iazolium iodide I Ego-CH3 N-Cyclopentenylpyrrolidine (2.7 grams) and 2-[2- acetanilidovinyl]-3-ethylbenzothiazolium iodide (9 grams) in ethanol (25 ml.) were shaken together at room temperature for one-half hour. The dye product formed was filtered off and recrystallized from ethanol to remove magenta and blue impurities. The orange dye was obtained as maroon leaflets, m.p. 297-299C. with decomp. (darkens at 290C.) in 2.1 grams (23 percent) yield.

EXAMPLE 9 N-Cyclopentenylpyrrolidine This compound was prepared in the manner described by G.'Stark, et al., J. Am. Chem. Soc. 85, 216 (1963).

For the preparation of photographic emulsions, the new dyes of the invention are advantageously incorporated in the finished silver halide emulsion and should, of course, be uniformly distributed throughout the emulsion. The method of incorporating dyes in emulsions are relatively simple and well known to those skilled in the art of emulsion making. For example, it is convenient to add the dyes from solutions in appropriate solvents, in which the solvent selected should have no deleterious effect on the ultimate light-sensitive materials. Methanol, isopropanol, pyridine, etc., alone or in combination have proven satisfactory as solvents'for the majority of the new dyes of the invention. The type of silver halide emulsions that are sensitized with the new dyes include any of those prepared with hydrophilic colloids that are known to be satisfactory for dispersing light-sensitive silver halides, for example,

emulsions prepared with hydrophilic colloids, such as vention can also contain such addenda as chemical sennatural materials, e.g.,gelatin,albumin, agar-agar, gum sitizers, e.g., sulfur sensitizers (e.g., allyl thiocarbaarabic, alginic acid, etc., and synthetic hydrophilic mide, thiourea, allylisothiocyanate, cystine, etc.), variresins, e.g., polyvinyl alcohol, polyvinyl pyrrolidone, ous gdui compounds (eIgIpotassium chloroaurate, cellulose ethers, partially hydrolyzed cellulose acetate, auric trichloride, etc.) (see Baldsiefen U. S. Pat. No. etc. 2,540,085, issued Feb. 6, 1951;Damschroder U. S. Pat.

The concentration of the new dyes in the emulsions No, 2,597,856, issued May 27, 1952 and Yutzy et al. U. an be id y Varied, generally from about 5 to S. Pat. No. 2,597,915, issued May 27, 1952), various about 100 mg. per liter of flowable emu sio T e palladium compounds such as palladium chloride specific concentration will vary according to the type (Baldsiefen U. S. Pat. No. 2,540,086, issued Feb. 6, of light-sensitive material in the emulsion and accord- 1951), potassium chloropalladate (Stauffer et al. U. S. ing to the effects desired. The most advantageous dye Pat. No. 2,598,079, issued May 27, 1952), etc., or mixc n trati n for any gi en mulsion an be r ad ly tures ofsuch sensitizers; antifoggants, such as ammonidetermined by making the tests and observations m chloroplatinate (Trivelli et al. U. S. Pat. No. customarily used in the art of emulsion making. The 2,566,245, issued Aug. 28, 1951), ammonium emulsions are coated to advantage on any of the supchloroplatinite (Trivelli et al. U. S. Pat. No. 2,566,263, port materials commonly used for photographic eleissued Aug. 28, 1951), benzotriazole,

en for e p p p glass cellulose derivatives; nitrobenzimidazole, S-nitroindazole, benzidine, mersuch as cellulose acetate, cellulose acetate-propionate, captans, etc. (see Mees-The Theory of the Photocellulose nitrate, etc., synthetic resins, such as ra hi Process, MacMillan Pub., 1942, page 460), or polystyrene, polyethylene terephthalate and other mixtures thereof; hardeners, such as formaldehyde polyesters, polyamides, such as nylon,and the like. (Mill U, 5, P t, N 1,763,533, i d J 10,

To prepare a gelatino-silver halide emulsion desen- 1930 chrome l U p 1 7 3 533 l sitized with One Of the new y e ll ing al (Brunken U. S. Pat. No. 1,870,354, issued Aug. 9, procedure is satisfactory: A quantity of dye is dissolved 1932), dibromacrolein (Block et al. British Pat. No. in a suitable solvent, and a volume of this solution con- 406,750, t d Mar, 8, 1934), etc.; color couplers, taining the desired amount Of dye is lowly added with such as those described in Salminen et al. U. S. Pat. No. intimate mixing to about 1,000 cc. of light-sensitive 2,423,730, issued July 7, 1947, Spence and Carroll U. gelatino-silver halide emulsion. With most of the new 5, P N 2, 40,77 i d Jun 2 1953, or y from about 10 i0 20 gof y 1 liter of emul tures of such addenda. Dispersing agents for color sion suffices to produce the desired sensitizing effect couplers, h as th t f h i J n r 1, U, s with the ordinary gelatine-silverhalides including silver P N 2,322,027, i d J 15, 1943, and M n s hl ri mi m i chlorobromide. et al. 0. s. Pat. No. 2,304,940, issued Dec. 15, 1942, chlorobromoiodide, etc., emulsions. fine-grain can also be employed in [he above described emu]- emulsions which include most of the ordinary emsigns,

P y gelatlno'silver chloride emulsions, Somewhat The invention has been described in detail with parlarger concentrations of dye may be n es ry to ticular reference to preferred embodiments thereof but secure optimum sensitizing effect. hi e th Pr g 40 it will be understood that variations and modifications has dealt t emulsions Comprising gelatin, it will be can be effected within the spirit and scope of the invend r d that these remarks apply generally to any tion as described hereinabove and as defined in the apemulsions in which a part of all of the gelatin is subpended claims.

stituted by another suitable hydrophilic colloid such as We claim:

those previously mentioned. 1. A cyanine dye compound selected from those hav- The above statements are only illustrative and are i o of the f ll win formul Hz H2 and O i --Z.

not to be understood as limiting the invention in any wherein m and n each represents a positive integer of sense,as it will be apparent that the new dyes can be infrom 1 to 2; R and R each represents a member corporated by other methods in many of the emulsions selected from the group consisting of an alkyl group customarily used in the art. For instance, in a less containingfrom one to 12 carbon atoms, an ally] group,

preferred method, the dyes can be incorporated by a phenyl and a naphthyl group; and, Z and Z, each bathing a plate or film bearing an emulsion, in a solurepresents the non-metallic atoms necessary to tion of the dye. complete a' heterocyclic nucleus selected from the Photographic silver halide emulsions, such as those group consisting of a thiazole nucleus, a benzothiazolc listed above, containing the sensitizing dyes of the innucleus, a naphthothiazole nucleus, at thianaphtheno- 3,715,351 ll 12 l 't t l e an OXaZOle s, a thiazole nucleus, 21 benzothiazole nucleus, 21

benzoxazole nucleus, a naphthoxazole nucleus, a naphthothiazole nucleus, a thianaphtheno-7',6,4,5- selenazole nucleus, a benzoselenazole nucleus, a thiazole nucleus, an oxazole nucleus, 21 benzoxazole naphthoselenazole nucleus, a thiazoline nucleus, a 2- nucleus, a naphthoxazole nucleus, 21 selenazole quinoline nucleus, a 4-quinoline nucleus, a l-isoquin- 5 nucleus, a benzoselenazole nucleus, a oline nucleus, a 3-isoquinoline nucleus, a 3,3-dialkylinnaphthoselenazole nucleus, a thiazoline nucleus, a 2- dolenine nucleus, a pyridine nucleus, an imidazole quinoline nucleus, at 4-quinoline nucleus, al-isoquinnucleus, a benzimidazole nucleus and a oline nucleus, a 3,3-dialkylindolenine nucleus, a

naphthimidazole nucleus. pyridine nucleus, an imidazole nucleus, a 2. A cyanine dye having the following formula: benzimidazole nucleus and a naphthimidazole nucleus.

4. A cyanine dye having the following formula:

I n z RI-'I(- H= H)n-l-c=oH oH=o cm Hz H2 wherein n represents a positive integer of from i to if R wherein m and n represents a positive integer of from 1 represents a member selected from the group consistto 2; R and R each represents a member selected from ing of an alkyl group containing from one to four the group consisting of an alkyl group containing from atoms, an allyl group, a phenyl group and a naphthyl one to four carbon atoms, an allyl group, a phenyl group; and,Zrepresents the non-metallic atoms necesgroup and a naphthyl group; and, Z and Z, each sary to complete a heterocyclic nucleus selected from represents the non-metallic atoms necessary to the group consisting of a thiazole nucleus, a complete a heterocyclic nucleus selected from the benzothiazole nucleus, 21 naphthothiazole nucleus, a g p Consisting Ofathialole nucleus, 8 benzothiazole thianaphtheno-7',6,4,5-thiazole nucleus, an oxazole ycleu m naphthoth igzole nucleus, a thianaphthcnonucleus, a benzoxazole nucleus, naphthoxazole nucleus, an OXaZOle nucleus, a nucleus, a selenazole nucleus, a benzoselenazole benzoxalole nucleus, 8 naphthoxalole nucleus, a nucleus, a naphthoselenazole nucleus, a thiazoline Selenazole nucleus, a benzoseleflalole nucleus, nucleus, a 2-quinoline nucleus, a4-quinoline nucleus, a naPhthoselenazole nucleus, 3 thlazoline nucleus, 3 l-isoquinoline nucleus, a 3-isoquinoline nucleus, a 3,3 qlfmoline nucleus: 3 'fl l nucleus a q dialkylindolenine nudeus, a pyridine nucleus, an olme nucleus,a3-1soqu1nol ne nucleus,a3,3-dialkylinimidazole nucleus, a benzimidazole nucleus and a dolenme nucleus a Pyridine nucleus an imldazole naphthimidazola nucleus nucleus, 3. benzimidazole nucleus and a 3. A cyanine dye having the following formula: 40 naphthlmldazole nucleus I? M 1' "Z I "Z R-I-i(-cH=cH 1o=oH-oH=o C=CH-CH=C (CH=CH)m-1I IR| z Hr wherein m and n represents a positive integer of from 1 5. 2,5-bis[(3-ethyl-2-benzothiazolinylidene)-ethyto 2; R and R, each represents a member selected from lidenelcyclopentanone. the group consisting of an alkyl group containing from 6. 2,5-bis[(1-ethylnaphtho[l,2-d]thiazolin-2- one to four carbon atoms, an allyl group, a phenyl ylidene)ethylidene]cyclopentanone. group and a naphthyl group; and, each Z represents the 7. 2,5-bis[( 1,3,3-trimethyl2-indolinylidene)-ethynon-metallic atoms necessary to complete a heterolidene1cyclopentanone. cyclic nucleus selected from the group consisting of a 2-[( thy z az y y lcyclopentanone. 

1. A cyanine dye compound selected from those having one of the following formulas:
 2. A cyanine dye having the following formula:
 3. A cyanine dye having the following formula:
 4. A cyanine dye having the following formula:
 5. 2,5-bis((3-ethyl-2-benzothiazolinylidene)-ethylidene)cyclopentanone.
 6. 2,5-bis((1-ethylnaphtho(1,2-d)thiazolin-2-ylidene)ethylidene)cyclopentanone.
 7. 2,5-bis((1,3,3-trimethyl-2-indolinylidene)-ethylidene)cyclopentanone. 